Fig. 1.

Radiological assessments. Cement loosening after vertebroplasty for osteoporotic vertebral fracture with intravertebral cleft. Cement loosening was defined as a low-intensity area between the vertebral body and the bone cement on CT 6 months after percutaneous vertebroplasty (A: sagittal, B: coronal). Wedging angle of the fractured vertebrae measured as the angle between cephalic upper and lower endplates on a lateral radiogram with the patient in the sitting position (C). Intravertebral instability of the affected vertebra measured as the difference between the wedging angle on lateral radiograms with the patient in the sitting and supine positions (C, D: α-β). Spinous process fracture (E: sagittal, CT). Split vertebrae (F: sagittal, CT). CT, computed tomography.